Hybrid compress bone fixator

Abstract

A stem for fixating a prosthesis to a bone can include a first stem portion and a second stem portion. The first stem portion can extend substantially along a longitudinal axis. The first stem portion can include a distal portion. The second stem portion can extend substantially distally from the distal portion of the first stem portion along the longitudinal axis. The second stem portion can be securable to the bone independent of the first stem portion, and the second stem portion can include a distal portion couplable to a compress assembly.

1 . A method for fixating a prosthesis to a bone, the method comprising:
 inserting a proximal portion of a stem of the prosthesis into the bone in an interference fit to secure the proximal portion to the bone;   inserting a distal portion of the stem into the bone, the distal portion connected to the proximal portion, the distal portion including an outer diameter smaller than an outer diameter of the proximal portion, and the outer diameter of the distal portion configured to be smaller than a diameter of an intramedullary canal of the bone; and   securing a fastener through the bone and through a bore of the distal portion to secure the distal portion of the stem to the bone.   
     
     
         2 . The method of  claim 1 , wherein the distal portion has a polished outer surface to limit bone on-growth. 
     
     
         3 . The method of  claim 2 , wherein the proximal portion includes an outer surface comprising a porous material configured to promote bone ingrowth. 
     
     
         4 . The method of  claim 3 , wherein inserting the proximal portion of the stem of the prosthesis into the bone includes engaging the bone with a plurality of projections that extend radially along an outer surface of the proximal portion, wherein the plurality of projections extend axially along the proximal portion, and wherein the plurality of projections are spaced around a circumference of the proximal portion. 
     
     
         5 . The method of  claim 1 , further comprising:
 engaging a distal resected surface of the bone with a compress assembly secured to the distal portion of the stem.   
     
     
         6 . The method of  claim 5 , further comprising:
 securing a plurality of fasteners through the bone and through a plurality of bores of the distal portion to secure the distal portion of the stem to the bone.   
     
     
         7 . The method of  claim 1 , wherein the proximal portion and the distal portion are connected by one of a fillet, chamfer, bevel, or round. 
     
     
         8 . The method of  claim 1 , wherein an outer surface of the proximal portion is made of Ti6Al4V and has a porous structure that is configured to mimic a porous structure of human cancellous bone. 
     
     
         9 . The method of  claim 1 , wherein the distal portion of the distal portion of the stem includes a threaded portion configured to receive a fastener to secure the distal portion to a biasing element. 
     
     
         10 . The method of  claim 1 , wherein the diameter of the distal portion is constant along an axial length of the distal portion between a distal end of the distal portion and a transition between the proximal portion and the distal portion. 
     
     
         11 . A method for fixating a prosthesis to a bone, the method comprising:
 inserting a proximal portion of a stem of the prosthesis into the bone in an interference fit to secure the proximal portion to the bone;   inserting a distal portion of the stem into the bone, the distal portion connected to the proximal portion, the distal portion including an outer diameter smaller than an outer diameter of the proximal portion, and the outer diameter of the distal portion configured to be smaller than a diameter of an intramedullary canal of the bone;   engaging a distal resected surface of the bone with a compress assembly secured to the distal portion of the stem; and   securing a fastener through the bone and through a bore of the distal portion to secure the distal portion of the stem to the bone.   
     
     
         12 . The method of  claim 11 , further comprising:
 securing a plurality of fasteners through the bone and through a plurality of bores of the distal portion to secure the distal portion of the stem to the bone.   
     
     
         13 . The method of  claim 12 , wherein the distal portion has a polished outer surface to limit bone on-growth. 
     
     
         14 . The method of  claim 13 , wherein the proximal portion includes an outer surface comprising a porous material configured to promote bone ingrowth. 
     
     
         15 . The method of  claim 14 , wherein inserting the proximal portion of the stem of the prosthesis into the bone includes engaging the bone with a plurality of projections that extend radially along an outer surface of the proximal portion, wherein the plurality of projections extend axially along the proximal portion, and wherein the plurality of projections are spaced around a circumference of the proximal portion. 
     
     
         16 . A method for fixating a prosthesis to a bone, the method comprising:
 inserting a stem of the prosthesis into the bone so that a proximal portion of the stem engages the bone an interference fit to secure the proximal portion to the bone, the stem including a distal portion connected to the proximal portion, the distal portion including an outer diameter smaller than an outer diameter of the proximal portion, and the outer diameter of the distal portion configured to be smaller than a diameter of an intramedullary canal of the bone;   engaging a distal resected surface of the bone with a compress assembly secured to the distal portion of the stem; and   securing a plurality of fasteners through the bone and through a plurality of bores of the distal portion to secure the distal portion of the stem to the bone.   
     
     
         17 . The method of  claim 16 , wherein the distal portion has a polished outer surface to limit bone on-growth; and wherein the proximal portion includes an outer surface comprising a porous material configured to promote bone ingrowth. 
     
     
         18 . The method of  claim 17 , wherein inserting the stem of the prosthesis into the bone includes engaging the bone with a plurality of projections that extend radially along an outer surface of the proximal portion, wherein the plurality of projections extend axially along the proximal portion, and wherein the plurality of projections are spaced around a circumference of the proximal portion. 
     
     
         19 . The method of  claim 18 , wherein the compress assembly includes a housing configured to receive the distal portion of the stem therein, the housing including a proximal portion engageable with the distal resected portion of the bone. 
     
     
         20 . The method of  claim 19 , wherein the compress assembly includes a biasing element located within the housing and configured to engage the distal portion of the stem and the housing to bias the housing proximally and to bias the distal portion of the stem distally.